Possible effects of antiferromagnetic crystalline phases on the temperature dependence of coercivity for Ni and Co nanowires obtained by electrodeposition

Abstract

Herein, the structural and magnetic properties of Ni and Co nanowires obtained by electrodeposition on alumina membranes are studied. Structural analysis shows the coexistence of Ni and Co metallic phases as well as NiO and CoO, which are associated with the preparation method. The magnetic study suggests the possibility of unidirectional anisotropy as a possible mechanism on the magnetization reversal in nickel and cobalt nanowires. For the experimental curves of coercivity versus temperature, there exists a critical value, below which only the dipole interactions are predominant. Above this temperature, the dipole magnetocrystalline and magnetostrictive energy compete in a complicated way. Alongside these three contributions, the coexistence of the “local unidirectional coupling” of antiferromagnetic nanoparticles that engage in random directions on nanowires is proposed.